Optical fingerprint sensor package

ABSTRACT

An optical fingerprint sensor package includes a carrier, an image sensor, at least one LED (light emitting diode), and a molding compound. The carrier is penetrated with a first cavity. The carrier has a peripheral region surrounding the first cavity. The peripheral region is provided with first conductive pads thereon. The image sensor is mounted in the first cavity and electrically connected to the first conductive pads by conductive wire bonding. The LED is mounted to correspond to the peripheral region of the carrier. The molding compound covers the peripheral region of the carrier, the image sensor, and the at least one LED, and fills the first cavity to fix the image sensor in the first cavity and expose the bottom of the image sensor to an external space.

REFERENCE TO RELATED APPLICATION

This Application is based on U.S. Provisional Application Ser. No.62/425,715, filed 23 Nov. 2016.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a package structure, particularly to anoptical fingerprint sensor package.

Description of the Related Art

Typically, fingerprints have a number of features including ridges,valleys, and finer points. A finer point includes a bifurcation where aridge is branched and an end point where the ridge ends. The fingerprintcan be regarded as a unique biometric data since its characteristicdistribution is different every person and two people cannot have thesame fingerprints. Thus, the use of biometric data such as fingerprintsin a security system may ensure efficient and accurate protection forthe district that requires security, movable assets or the like.

A fingerprint recognition apparatus for acquiring an image of thefingerprint may be classified into a semiconductor type apparatus andoptical type apparatus, and an optical fingerprint recognition apparatusis widely used rather than a semiconductor fingerprint recognitionapparatus. The optical fingerprint recognition apparatus includes lightsources, an image sensor and a total internal reflection prism glass inwhich light proceeds through the incident surface of the prism, isreflected at the contact surface of the prism, and is emitted from theexit surface of the prism. When a finger is put on the contact surfaceof the prism, light undergoes diffused reflectance at the points wherethe ridges of the fingerprint are in contact with the glass. However, nolight undergoes the diffused reflectance at the points where the valleysof the fingerprint are in contact with the glass. Thus, the lightemitted from the exit surface of the prism exhibits the characteristicsof the fingerprint. Refer to FIG. 1. The conventional opticalfingerprint recognition package includes a supporting base 10, anisolated base 12, a first adhesive 14, a second adhesive 16, LEDs 18, animage sensor 20, and a transparent colloid 22. The isolated base 12 islocated in the supporting base 10. The LEDs 18 are located on theisolated base 12 through the first adhesive 14. The image sensor 20 islocated on the supporting base 10 through the second adhesive 16. Thetransparent colloid 22 is located in the supporting base 10 to cover theisolated base 12, the first adhesive 14, the second adhesive 16, theLEDs 18, and the image sensor 20. However, due to the existence of thesupporting base 10, the whole volume of the conventional opticalfingerprint recognition package is larger. As a result, the conventionaloptical fingerprint recognition package is difficultly embedded in apanel or a glass cover.

To overcome the abovementioned problems, the present invention providesan optical fingerprint sensor package.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide an opticalfingerprint sensor package, which penetrates a carrier to form a cavityand places an image sensor in the cavity to decrease the thickness andvolume of the optical fingerprint sensor package.

To achieve the abovementioned objectives, the present invention providesan optical fingerprint sensor package, which comprises a carrier, animage sensor, at least one LED (light emitting diode), and a moldingcompound. The carrier is penetrated with a first cavity. The carrier hasa peripheral region surrounding the first cavity. The peripheral regionis provided with first conductive pads thereon. The image sensor ismounted in the first cavity and electrically connected to the firstconductive pads by conductive wire bonding. The LED is mounted tocorrespond to the peripheral region of the carrier. The molding compoundcovers the peripheral region of the carrier, the image sensor, and theat least one LED, and fills the first cavity to fix the image sensor inthe first cavity and expose the bottom of the image sensor to anexternal space.

In an embodiment of the present invention, the at least one LED ismounted on the peripheral region of the carrier through an adhesive bysurface-mount technology (SMT).

In an embodiment of the present invention, the adhesive is a red glue ora silver paste.

In an embodiment of the present invention, the height of the bottom ofthe at least one LED is higher than the height of the top of the imagesensor.

In an embodiment of the present invention, the peripheral region of thecarrier is further provided with second conductive pads thereon andpenetrated with at least one second cavity. The at least one LED ismounted in the at least one second cavity of the peripheral region, themolding compound fills the at least one second cavity to fix the atleast one LED in the at least one second cavity and expose the bottom ofthe at least one LED to the external space. The at least one LED iselectrically connected to the second conductive pads by conductive wirebonding.

In an embodiment of the present invention, the at least one secondcavity further comprises a plurality of second cavities, and the atleast one LED further comprises a plurality of LEDs (light emittingdiodes) respectively mounted in the plurality of second cavities.

In an embodiment of the present invention, the height of the top of thecarrier is higher than the height of the top of the at least one LED.

In an embodiment of the present invention, the carrier is a substrate ora lead frame.

In an embodiment of the present invention, the at least one LEDcomprises a plurality of LEDs (light emitting diodes).

In an embodiment of the present invention, the at least one LED is aninfrared (IR) LED.

In an embodiment of the present invention, the image sensor is acharge-coupled device (CCD) or a complementary metal-oxide-semiconductor(CMOS).

Below, the embodiments are described in detail in cooperation with thedrawings to make easily understood the technical contents,characteristics and accomplishments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an optical fingerprint sensor package in theconventional technology;

FIG. 2 is a top view of an optical fingerprint sensor package accordingto the first embodiment of the present invention;

FIG. 3 is a sectional view taken along Line A-A′ of FIG. 2;

FIG. 4 is a top view of the optical fingerprint sensor package accordingto the second embodiment of the present invention; and

FIG. 5 is a sectional view taken along Line B-B′ of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts. In the drawings, the shape and thickness may be exaggerated forclarity and convenience. This description will be directed in particularto elements forming part of, or cooperating more directly with, methodsand apparatus in accordance with the present disclosure. It is to beunderstood that elements not specifically shown or described may takevarious forms well known to those skilled in the art. Many alternativesand modifications will be apparent to those skilled in the art, onceinformed by the present disclosure.

Refer to FIG. 2 and FIG. 3. The first embodiment of the opticalfingerprint sensor package of the present invention is introduced asfollows. The optical fingerprint sensor package comprises a carrier 24,an image sensor 26, at least one LED (light emitting diode) 28, and amolding compound 30. For example, the carrier 24 is a substrate or alead frame, and the LED 28 is an infrared (IR) LED, and the image sensor26 is a charge-coupled device (CCD) or a complementarymetal-oxide-semiconductor (CMOS). The carrier 24 is penetrated with afirst cavity 32. The carrier 24 has a peripheral region 34 surroundingthe first cavity 32. The peripheral region 34 is provided with firstconductive pads 36 thereon. The image sensor 26 is mounted in the firstcavity 32 and electrically connected to the first conductive pads 36 byconductive wire bonding. In the first embodiment, there is a pluralityof LEDs (light emitting diodes) 28. The plurality of LEDs 28 is mountedto correspond to the peripheral region 34 of the carrier 24. In thefirst embodiment, each of the plurality of LEDs 28 is mounted on theperipheral region 34 of the carrier 24 through an adhesive 38 bysurface-mount technology (SMT). For example, the adhesive 38 is a redglue or a silver paste. In order to prevent the side light of each LED28 from interfering with the image sensor 26, the height of the bottomof each LED 28 is higher than the height of the top of the image sensor26. The molding compound 30 covers the peripheral region 34 of thecarrier 24, the image sensor 26, and each LED 28, and fills the firstcavity 32 to fix the image sensor 26 in the first cavity 32 and exposethe bottom of the image sensor 26 to an external space. The carrier 24is not provided with any substrate thereunder. The thickness of theimage sensor 26 is similar to that of the carrier 24. In addition, thethickness of the LED 28 is very thin. As a result, the present inventionpenetrates the carrier to form the cavity and places the image sensor inthe cavity to decrease the thickness and volume of the opticalfingerprint sensor package, such that the optical fingerprint sensorpackage is easily embedded in a thin panel or a thin glass cover.

Refer to FIG. 4 and FIG. 5. The second embodiment of the opticalfingerprint sensor package of the present invention is introduced asfollows. The optical fingerprint sensor package comprises a carrier 24,an image sensor 26, at least one LED (light emitting diode) 28, and amolding compound 30. For example, the carrier 24 is a substrate or alead frame, and the LED 28 is an infrared (IR) LED, and the image sensor26 is a charge-coupled device (CCD) or a complementarymetal-oxide-semiconductor (CMOS). The carrier 24 is penetrated with afirst cavity 32. The carrier 24 has a peripheral region 34 surroundingthe first cavity 32. The peripheral region 34 is provided with firstconductive pads 36 and second conductive pads 40 thereon and penetratedwith at least one second cavity 42. The image sensor 26 is mounted inthe first cavity 32 and electrically connected to the first conductivepads 36 by conductive wire bonding. In the second embodiment, there area plurality of LEDs (light emitting diodes) 28 and a plurality of secondcavities 42. The plurality of LEDs 28 is mounted to correspond to theperipheral region 34 of the carrier 24. In the second embodiment, theplurality of LEDs 28 is respectively mounted in the plurality of secondcavities 42 of the peripheral region 34. In order to prevent the sidelight of each LED 28 from interfering with the image sensor 26, theheight of the top of the carrier 24 is higher than the height of the topof each LED 28, such that the carrier 24 blocks the side light of eachLED 28. The plurality of LEDs 28 is electrically connected to the secondconductive pads 40 by conductive wire bonding. The molding compound 30covers the peripheral region 34 of the carrier 24, the image sensor 26,and each LED 28, fills the first cavity 32 to fix the image sensor 26 inthe first cavity 32 and expose the bottom of the image sensor 26 to anexternal space, and fills the plurality of second cavities 42 to fix theplurality of LEDs 28 in the plurality of second cavities 42 and exposethe bottom of the plurality of LEDs 28 to the external space. Thecarrier 24 is not provided with any substrate thereunder. The thicknessof the image sensor 26 is similar to that of the carrier 24. Inaddition, the thickness of the LED 28 is very thin. As a result, thepresent invention penetrates the carrier to form the cavity and placesthe image sensor in the cavity to decrease the thickness and volume ofthe optical fingerprint sensor package, such that the opticalfingerprint sensor package is easily embedded in a thin panel or a thinglass cover.

In conclusion, the present invention penetrates the carrier toaccommodate the image sensor, thereby reducing the thickness and volumeof the optical fingerprint sensor package.

The embodiments described above are only to exemplify the presentinvention but not to limit the scope of the present invention.Therefore, any equivalent modification or variation according to theshapes, structures, features, or spirit disclosed by the presentinvention is to be also included within the scope of the presentinvention.

What is claimed is:
 1. An optical fingerprint recognition sensor packagecomprising: a carrier penetrated with a first cavity, the carrier havinga peripheral region surrounding the first cavity, the peripheral regionis provided with first conductive pads thereon; an image sensor mountedin the first cavity and electrically connected to the first conductivepads by conductive wire bonding; at least one LED (light emitting diode)mounted to correspond to the peripheral region of the carrier; and amolding compound covering the peripheral region of the carrier, theimage sensor, and the at least one LED, and filling the first cavity tofix the image sensor in the first cavity and expose a bottom of theimage sensor to an external space.
 2. The optical fingerprint sensorpackage according to claim 1, wherein the at least one LED is mounted onthe peripheral region of the carrier through an adhesive bysurface-mount technology (SMT).
 3. The optical fingerprint sensorpackage according to claim 2, wherein the adhesive is a red glue or asilver paste.
 4. The optical fingerprint sensor package according toclaim 2, wherein a height of a bottom of the at least one LED is higherthan a height of a top of the image sensor.
 5. The optical fingerprintsensor package according to claim 1, wherein the peripheral region ofthe carrier is further provided with second conductive pads thereon andpenetrated with at least one second cavity, the at least one LED ismounted in the at least one second cavity of the peripheral region, themolding compound fills the at least one second cavity to fix the atleast one LED in the at least one second cavity and expose a bottom ofthe at least one LED to the external space, and the at least one LED iselectrically connected to the second conductive pads by conductive wirebonding.
 6. The optical fingerprint sensor package according to claim 5,wherein the at least one second cavity further comprises a plurality ofsecond cavities, and the at least one LED further comprises a pluralityof LEDs (light emitting diodes) respectively mounted in the plurality ofsecond cavities.
 7. The optical fingerprint sensor package according toclaim 5, wherein a height of a top of the carrier is higher than aheight of a top of the at least one LED.
 8. The optical fingerprintsensor package according to claim 1, wherein the carrier is a substrateor a lead frame.
 9. The optical fingerprint sensor package according toclaim 1, wherein the at least one LED comprises a plurality of LEDs(light emitting diodes).
 10. The optical fingerprint sensor packageaccording to claim 1, wherein the at least one LED is an infrared (IR)LED.
 11. The optical fingerprint sensor package according to claim 1,wherein the image sensor is a charge-coupled device (CCD) or acomplementary metal-oxide-semiconductor (CMOS).